code: def _split_feature_trait(ft):
      """Feature is up to first '_'. Ex. 'line_color' => ['line', 'color']"""
      ft = ft.split("_", 1)
      return ft if len(ft) == 2 else [*ft, None]
  
file_path: bokeh/src/bokeh/plotting/_renderer.py
imports: from __future__ import annotations
  import logging
  import sys
  from collections.abc import Iterable
  import numpy
  from ..core.properties import ColorSpec
  from ..models import ColumnarDataSource, ColumnDataSource, GlyphRenderer
  from ..util.strings import nice_join
  from ._legends import pop_legend_kwarg, update_legend
label_desc: Use image node_id 8 for calling a global function with example usage: _split_feature_trait(ft) and returns: unknown